1. Field of the Invention
The present invention relates to a mobile navigation system for guiding a driver of a vehicle from a present position to a destination place set by the driver. More particularly, the invention relates to a mobile navigation system having such a function that when the vehicle approaches a stop position at which a driver of a vehicle must stop the vehicle, the navigation system produces an acoustic or visual presentation informing the driver that the vehicle approaches the stop position to call the driver's attention to the vehicle approaching to the stop position.
2. Description of the Related Art
A mobile navigation system is widely used. In the navigation system, a driver of a vehicle enters a destination place to the navigation system. Upon entering the destination place into the navigation system, the navigation system looks up an appropriate route from an original point to the designation place in a road map data base (the route may be a route having the shortest distance from the start point to the destination, a route having the shortest time taken for the vehicle to reach the destination, or others), and guides the driver to the destination along the searched route by the utilization of a display or vocal guide.
In searching the appropriate route, some type of mobile navigation system utilizes traffic information (position data on traffic jam, road-closed information by accident or road construction or maintenance, lane-regulated locations) delivered from a traffic infrastructure system, in addition to the road map data base.
Conventionally, there is no mobile navigation system capable of notifying a driver of the stop positions located ahead of the traveling vehicle, such as an intersection with a stop road sign, an intersection with a yield road sign where a yielded road intersects the road where the vehicle is running, or a railroad crossing. When the driver first travels through a region with a number of intersections, although no traffic signal exists in particular, but the road signs instructing the driver to stop the vehicle and remain standing for watching around, he must frequently and carefully check whether the passing intersection is a stop position during his driving. As a result, heavy stress is imposed on the driver.